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Electroencephalographic activity in children under enflurane anesthesia
Insights
Pediatric patients undergoing enflurane anesthesia may experience electrographic seizure activity, particularly with moderate hypocapnia (low CO2 levels). This seizure risk increases at enflurane concentrations of 3% or higher.
Area of Science:
- Anesthesiology
- Pediatric Neurology
- Neurophysiology
Background:
- Enflurane is an anesthetic agent used in pediatric patients.
- Central nervous system excitability can be affected by anesthetic agents and blood gas levels.
- Previous studies in adults indicated potential for increased central nervous system excitability with enflurane.
Purpose of the Study:
- To investigate the occurrence of electrographic seizure activity in children under enflurane anesthesia.
- To assess the relationship between enflurane concentration, PaCO2 levels, and seizure activity in pediatric patients.
Main Methods:
- Recorded electroencephalogram (EEG), end-tidal CO2, electromyography (EMG), eye movements, and electrocardiogram (ECG) in 17 children.
- Administered enflurane anesthesia combined with nitrous oxide (N2O) and oxygen (O2).
- Monitored spontaneous and controlled ventilation, including periods of hyperventilation.
Main Results:
- Generalized high-voltage epileptic activity (grand mal type) occurred in 3% of subjects with PaCO2 below 32 mmHg at 4% enflurane.
- Electrographic seizure activity (poly-spike-suppression type) was observed in 3 out of 8 subjects at 3% enflurane.
- Motor manifestations accompanied electrographic seizures in some cases, particularly with PaCO2 levels around 31 mmHg.
Conclusions:
- Electrographic seizure activity is a common finding in children receiving enflurane anesthesia at concentrations of 3% or higher, especially with moderate hypocapnia.
- Hypocapnia appears to be a significant factor contributing to seizure activity during enflurane anesthesia in pediatric populations.
- These findings highlight the importance of monitoring blood gas levels during enflurane anesthesia in children to mitigate seizure risks.
Abstract:
EEG, end-tidal CO2, neck muscle EMG, eye movements, and ECG were recorded in 17 children undergoing enflurane anesthesia combined with N2O and O2. All subjects were classified in the lowest risk group and had normal pre-anesthetic EEG recordings. Eleven subjects were breathing spontaneously and six were under controlled ventilation. Thirteen subjects were hyperventilated for short periods. As previously reported for adults, various signs of increased central nervous excitability appeared. At the enflurane concentration of 4% all three cases with PaCO2 below 32 mmHg showed generalized high voltage epileptic activity of grand mal type followed by several minutes of postictal slowing. One of these subjects also showed motor manifestations of the electrographic seizure activity. At 3% enflurane, three out of eight subjects showed electrographic seizure activity of poly-spike-suppression type. One of these children also had motor manifestations during this type of seizure activity at a PaCO2 of 31 mmHg. The results indicate that electrographic seizure activity is common among children with moderate hypocapnia at enflurane concentrations of 3% or more.